Mass storage devices, such as, hard disk drives, optical disk drives and the like, are well known components of an overall computer data storage system. Mass storage units have, in the past, usually been bolted and hardwired inside a computer chassis and were only removed from the chassis (with significant effort) in the event of needed maintenance or the device's failure.
Recently, however, mass storage devices have been developed which are in the form of modular units capable of being operatively and easily removably mounted within a computer chassis. Due to their modular nature, these portable individual mass storage devices are particularly useful when dedicated to the storage of important data which the user does not wish to be continuously in operative association with the computer for security and/or data integrity reasons. These individual portable mass storage devices can thus be removed easily from the computer chassis and stored in a secured location remote from the computer site until the data is needed, at which time the mass storage device is retrieved, transported and operatively reinstalled within the computer chassis (as by sliding the mass storage device into a "slot" in the computer chassis). In such a manner, the risks associated with unauthorized persons intentionally tampering, copying, or stealing the stored data (with the possible disastrous loss of valuable data) and/or unintentional data loss is minimized.
However, the transport of these portable mass storage devices presents its own risks of data loss during handling outside the chassis since they are readily susceptible to damage due to shocks received when the device is dropped, struck or otherwise mishandled. That is, when mishandled, the read/write head of the mass storage device may physically contact the data storage medium (i.e., a so-called "head crash") thereby damaging it to an extent that one or more of the stored data files is lost (i.e., irretrievable). Mass storage devices have included in the past mechanical means which locks the read/write head during transport, in addition to special software-controlled mechanical interlocks (e.g., which parks the head at a "storage" position and/or at a section of the disk on which no data is stored) as protective measures in an attempt to prevent head crash and data loss due to shock waves experienced by mishandling the mass data storage device. However, these conventional protective mechanical and software systems are usually insufficient in the case of severe shock waves (as when the mass storage device is dropped onto a surface). And, in any event, such mishandling may damage other shock sensitive components of the mass storage device (e.g., precision motors, control circuitry, et cetera).
Mass storage devices, including the more recently developed portable versions, have in the past been shock-isolated when operatively associated with the computer's chassis (see, for example, U.S. Pat. No. 4,705,257, the entire disclosure of which is expressly incorporated hereinto by reference). While shock-isolation of the mass storage device is important when it is operatively associated within the computer's chassis, it is equally (if not more) important for the device to be shock-isolated while removed from the chassis and while being transported to a different location.
Recently, however, a canister/drive assembly which shock isolates the drive at all times (i.e., not only when the drive is operatively associated within the computer chassis, but also when it is removed from the chassis for transport, et cetera) has been sold for more than one year prior to the date of this application. Such a canister/drive assembly 1 is schematically shown in accompanying FIG. 1 and is generally representative of the Series 3000 and 4000 systems previously sold by MDB Systems, Inc. (the Assignee of this application).
As is seen, the assembly 1 includes a canister 2 defining an interior space 2a in which a drive 3 was mounted for shock and vibration isolation via three substantially hemispherical elastomer isolators 4. The canister 2 was slidably received within a computer chassis 5 so that it could easily be removed therefrom (as indicated by the dashed line representation). The isolators 4 were positioned in a trilateral arrangement relative to the drive 3--that is, two of the isolators 4 were positioned between respective sides of the drive 3 and an adjacent portion of the canister 2, while the remaining isolator 4 was positioned between the front of the drive 3 and an adjacent front portion of the canister 2. This third isolator provides both tension and compression shock isolation forces and thus can, in effect, be considered as equivalent to a pair of isolators, one located at each end of drive 3.
While the canister/drive assembly 1 shown in FIG. 1 shock and vibration isolates the drive 3 at all times during operation and transport, it is too costly for most removable mass data storage applications--and tends to use a lot of internal space in the removable module 2 since the isolators 4 located on at least three sides of drive 3 consume space greatly in excess of the needed "sway space." Hence, the canister/drive assembly 1 tended to be cost and space effective only for those applications in which the shock and vibration isolation functions were an absolute necessity (i.e., as in military field computer applications) and where sufficient excess space is available. What has still been needed therefore, is a shock isolation mounting system for removable drives which is less costly and more space efficient so that general consumer computers may, for example, have shock protected removable drive modules. It is towards fulfilling this need that the present invention is directed.
According to the present invention, a mass storage device (which shall be hereinafter simply be termed "drive" for ease of reference) is provided in a portable canister which is sized and configured to be mounted removably and operatively within the chassis of a computer. Shock-isolation of the drive is provided through a pair of brackets rigidly mounted to respective lateral sides of the drive. Each of the brackets includes a pair of elastomeric shock-isolators connected to, and extending between, itself and an adjacent sidewall of the canister. The front and rear ends of the drive are thus left freely floating within the canister so that only the requisite "sway space" need be left at these locations (thus maximizing space efficiency). The drive thus is mounted within, and in spaced relation to, the canister so that shock waves experienced by the canister/drive assembly will be absorbed by the elastomeric shock-isolators and thus significantly minimize the risk of head crash during its transport --while yet remaining very economical and space efficient.
The canister also preferably houses a printed circuit board which is electrically coupled to the drive via any suitable conventional means (e.g., multiwire ribbon connectors, and the like). The printed circuit board may itself be mounted to the canister by means of elastomeric feet allowing the board to "float" (i.e., be resiliently displaced) when the canister/drive assembly is slid into operative engagement with the computer chassis so as to permit the pin connectors of the board to passively align with female connectors in the chassis.
Since the drive is mounted in spaced, shock-isolated relation to the canister, merely removing the canister from the computer chassis will not defeat the drive's shock isolation. Rather, shock isolation of the drive is provided at all times during the drive's physical transport from one location to another--even when it is disassociated from the computer chassis.
The removable nature of the canister/drive assembly of the invention presents a risk that the power supply (normally remaining with the chassis when the canister/drive is removed) will not be manually turned off by the user before the canister/drive is removed--as it should always be. Conversely, the user may forget to turn the chassis power off prior to the canister/drive being reinserted into the chassis. Either condition could cause arcing between the connector pins of the canister and their associated female connectors of the chassis and/or possible head/disk surface damage.
In order to avoid such problems (which arise primarily because of the readily removable nature of the drive canister) the present invention further includes a protective system for sensing relative separable movement between the male and female connectors and, in response to this sensed movement, to disable the power supply before the male and female connectors actually physically separate. Conversely, when the canister/drive is reinserted into the chassis, the protective system functions to supply power to the mass storage device only after the pins of the male connector have electrically connected with their respective female connectors. As can be appreciated, since the male and female connectors are electrically "dead" during making and breaking of their electrical connections during installation/removal of the canister drive assembly, arcing of the connector pins is prevented and possible head crashes are avoided. Other advantages also flow from this arrangement.
Preferably, the sensing and disabling functions of the protective system briefly mentioned above are achieved by control circuitry associated with at least one pin of a multiple pin connector which is shorter in length as compared to the other connector pins. In this manner, the shorter pin(s) is(are) the first to "break" and the last to "make" contact with its (their) female connector(s) (i.e., as compared to the longer pins) during removal/insertion of the canister drive assembly. The control circuitry thus serves to ensure that the power supply is switched off/on only while the longer pins are in physical and electrical contact with their female connectors during removal/insertion of the canister/drive assembly relative to the chassis.
Further advantages and features of this invention will become more clear after consideration is given to the following detailed description of the presently preferred exemplary embodiments.